Surgical fastener

ABSTRACT

Various embodiments of a non-deforming surgical fastener are discussed. In one embodiment, the fastener includes two legs and a backspan extending between the two legs. The fastener also includes a backspan thickness that is adapted to reduce the pressure and/or increase the holding strength applied to underlying materials. The non-deforming fastener is constructed and arranged to retain substantially the same shape before, during and after deployment into the target implantation site.

FIELD

Aspects relate to a surgical fastener.

BACKGROUND

Surgical fasteners are widely used in many different medical procedures.For example, staples, sutures, clips and other fasteners are commonlyused in laparoscopic and open surgical procedures.

SUMMARY

According to one embodiment a surgical fastener includes a first leg, asecond leg, and a backspan extending from the first leg to the secondleg. The backspan includes a central pad with a thickness greater than athickness of the backspan extending between the central pad and eitherthe first leg or second leg. The surgical fastener is a non-deformingfastener such that the first and second legs are constructed to remainin an open position after deployment of the fastener.

According to another embodiment, a method includes: deploying anon-deforming fastener into tissue, wherein a pressure applied to theunderlying tissue by the fastener is greater than or equal to 27.5 kPaand less than or equal to 275 kPa.

According to yet another embodiment, a surgical fastener includes afirst leg, a second leg, and a backspan extending from the first leg tothe second leg. The backspan has an area less than or equal to 10 mm²and greater than or equal to 0.25 mm². The surgical fastener is anon-deforming fastener such that the first and second legs areconstructed to remain in an open position after deployment of thefastener.

It should be appreciated that the foregoing concepts, and additionalconcepts discussed below, may be arranged in any suitable combination,as the present disclosure is not limited in this respect. Further, otheradvantages and novel features of the present disclosure will becomeapparent from the following detailed description of various non-limitingembodiments when considered in conjunction with the accompanyingfigures.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures may be represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. Various embodiments of the invention will now be described, byway of example, with reference to the accompanying drawings, in which:

FIG. 1 depicts a surgical fastener deployment device that may be used todeploy surgical fasteners in accordance with an aspect of the invention;

FIG. 2 depicts a perspective view of a surgical fastener in accordancewith an aspect of the invention;

FIG. 3 depicts a front view of the surgical fastener of FIG. 2;

FIG. 4 depicts a top view of the surgical fastener of FIG. 2

FIG. 5 depicts a perspective view of a surgical fastener with additionalbarbs in accordance with an aspect of the invention;

FIG. 6A depicts a perspective view of a surgical fastener with barbsarranged at different heights along the fastener leg in accordance withan aspect of the invention; and

FIG. 6B depicts a side view of the surgical fastener of FIG. 6A.

DETAILED DESCRIPTION

The inventors have appreciated the benefits associated with a surgicalfastener capable of applying reduced pressures over larger areas to anunderlying prosthetic and/or tissue. For example, a surgical fastenermight apply a larger total holding strength over a greater area, whilesubjecting an underlying prosthetic and/or tissue to a relatively lowpressure during insertion. Alternatively, a surgical fastener mightdistribute a desired holding force across a larger area to avoidapplying excessive pressure to an underlying prosthetic and/or tissue.In view of the above, the inventors have recognized that a surgicalfastener including a backspan with an increased surface area may be usedto provide reduced pressures and/or increased retention forces ascompared to typical surgical fasteners.

Depending on the particular application, some types of surgicalfasteners are designed to deform during deployment. For example, somesurgical staples have legs that curl inward into a closed position asthe staple is deployed into a tissue and/or prosthetic in order tosecure the staple at the desired implantation site. Therefore, as usedherein, a “deforming” fastener is one that is constructed and arrangedto change shape as it is deployed into the target implantation site.

In contrast to the above, as used herein, a “non-deforming” fastener isone that is constructed and arranged to retain substantially the sameshape before and after deployment into a target implantation site. Whilenon-deforming fasteners may undergo some permanent deformation such asdents or shape alterations due to contact with hard materials or due tosome amount of elastic deformation, the legs of such non-deformingfasteners are not designed or intended to bend or deform during normaluse. Instead, the legs of the surgical fasteners are deployed in an openposition and remain in the open position after deployment as well.

The surgical fasteners disclosed herein may be made from any appropriatematerial including various appropriate metals and polymers.Additionally, the material may be selected such that the surgicalfastener is non-absorbable or bioabsorable as the current disclosure isnot so limited. For example, a non-absorbable surgical fastener may bemade from: a stainless steel, such as 316L stainless steel, titanium, anickel titanium based alloy such as nitinol, polypropylene, a highdensity polyurethane, ultra high molecular weight polyethylene (UHMWPE),nylon, polyester or any other appropriate material. Appropriatebioabsorbable materials include, but are not limited to magnesium, zinc,manganese and iron, or their combination alloy, polylactic acid,polyglycolic acid, copolymers thereof, and the like.

The disclosed surgical fastener may also be manufactured in anyappropriate fashion. For example, the surgical fastener may beintegrally formed such that the fastener comprises a single monolithiccomponent. In other embodiments, the fastener may be assembled byforming separate portions of the fastener and attaching them togetherusing an adhesive, a welding process, or any suitable method orsubstance, as this aspect is not so limited.

For the sake of clarity, the embodiments depicted in the figures aredirected to a laparoscopic device. However, the current disclosure isnot limited to laparoscopic devices. Instead, the currently disclosedsurgical fasteners could be used in any appropriate device for thedeployment of a surgical fastener into tissue. For example, the surgicalfasteners could be used in an endoscopic device, a borescopic device, acatheter, a deployment device for use in “open” procedures, or any otherappropriate deployment device. Additionally, a device might use anynumber of surgical fasteners.

For the purposes of this application, a barb associated with thesurgical fastener is not considered to be part of a leg that it extendsfrom.

Turning now to the figures, embodiments related to a non-deformingsurgical fastener with a widened backspan capable of applying reducedpressures and/or increased holding strength to underlying materials isdescribed.

FIG. 1 depicts an exemplary fastener deployment device 1 for deployingone or more surgical fasteners into a prosthetic and/or tissue. Thedeployment device includes a handle 4 at a proximal end of the deviceand an actuation button such as a trigger 2 on the handle. Thedeployment device also includes a shaft 5 extending in a distaldirection from the handle 4. Actuating the trigger 2 moves fastenersinside shaft 5 in a direction from the proximal end 6 of the shaft tothe distal end 8, and deploys a distal-most surgical fastener from thedistal end 8 of the shaft 5. It should be understood that the deployedsurgical fastener may be deployed into any appropriate prosthetic whichmay be embodied by any number of different components or materials. Forexample, in one embodiment, the prosthetic may be a soft tissue repairfabric, such as a surgical mesh, used for repairing a hernia.

FIGS. 2-4 depict one embodiment of a non-deforming surgical fastener 10.In the depicted embodiment, the fastener 10 has two legs 20 extending ina distal direction. While two legs are depicted, it should be understoodthat any number of legs might be used. Each leg 20 includes a distal tipthat is adapted to be inserted into a prosthetic and/or tissue. In someembodiments, and as illustrated in the figures, the distal tips of thelegs 20 include sharpened points 52 though non-sharpened points are alsopossible. The legs 20 are connected to opposing ends of a backspan 36 toform a surgical fastener with a somewhat U-shaped profile. Other profileshapes are also possible. For example, the surgical fastener 10 may havea C-shaped profile or any other desirable profile as the currentdisclosure is not limited in this fashion. As shown in FIG. 2, the legs20 are in an open position. The legs 20 remain in the open positionafter deployment as well.

As seen in FIG. 2, the fastener may include outer corners 35 where theleg 20 and the backspan 36 meet. In the embodiment shown in FIG. 2, theouter corners 35 are rounded. However, in other embodiments, the outercorners 35 may be chamfered, angled or have any other suitable shape. Asseen in FIG. 3, the fastener also includes inner corners 33 where thelegs 20 and the backspan 36 meet. In the embodiment shown in FIG. 3, theinner corners 33 are rounded. However, similar to the above, in otherembodiments, the inner corners 33 may also be chamfered, angled or haveany other suitable shape.

In some embodiments, the surgical fastener includes an anchoring featuresuch as one or more barbs to keep the fastener anchored to theunderlying prosthetic and/or tissue once it has been deployed. Forexample, as shown in FIG. 2, barbs 54 may be located on the distal endsof legs 20 of the fastener. In the depicted embodiment, the barbs 54point away from the distal tips 52 of the legs toward the proximaldirection (away from the direction of deployment). Without wishing to bebound by theory, such barbs will increase the pull out force required toremove the fastener from the target implantation site. While theembodiment shown in FIG. 2 includes two barbs per leg, any number ofbarbs may be used, as this aspect is not so limited. For example, in theembodiment shown in FIG. 5, the legs have a third barb 55. In addition,barbs may be located on the legs, the backspan or on any other suitableportion of the fastener. It should also be understood that while barbshave been described above, any appropriate anchoring feature might beused including, but not limited to, surface roughness or other suitabletreatment to increase the pull out force of the surgical fastener.

In some embodiments, the anchoring feature may be provided at differentheights along the fastener leg. In the embodiment shown in FIG. 2, thebarbs 54 are arranged at the same height along leg 20. In otherembodiments, however, barbs may be arranged at different heights alongthe fastener legs. For example, in the embodiment shown in FIGS. 6A-6B,barbs 71 and 73 are positioned at different heights along leg 21.Without wishing to be bound by theory, barbs or other anchoring featuresat different heights along the fastener leg will engage with tissueand/or a prosthetic at multiple depths and may result in increased pullout resistance.

It should be appreciated that the barbs shown in the figures areillustrative examples and may be varied. For example, the barbs may havelonger lengths and may have any suitable angle and shape to provide pullout resistance. In addition, while FIG. 2 depicts the distal tip 52 ofleg 20 as being symmetrical, the distal tip of the fastener tip may beasymmetrical. For example, as shown in FIGS. 6A-6B, the distal tip 53 ofleg 21 is asymmetrical, where the left side of the tip is slanted andthe right side of the tip is vertical.

The inventors have also appreciated that certain barb orientations mayallow an increased width of the fastener backspan while satisfying theconstraints that arise with use of the fastener within the confinedspace of a shaft. As shown in FIG. 3, the fastener may have a width W1corresponding to the length between the two exterior sides of the legs20 that is sized to be delivered through an outlet of the deliveryshaft. In some cases, the barbs may be oriented to permit as wide abackspan width W1 as possible that still permits the fastener to bedelivered through the outlet of the delivery shaft. As shown in FIGS.2-3, in some embodiments, the barbs 54 may extend in a direction that isperpendicular to the width W1 (the barbs 54 extend in and out of thepage in FIG. 3 along the z-axis). Having the barbs oriented in this waymay permit the legs 20 to be spaced as far apart as possible within theconstraints of delivery through a surgical port, thereby increasing thebackspan width W1. However, other barb orientations are also possible.For example, in the embodiment shown in FIG. 5, the fastener has a thirdbarb 55 pointed in a direction that is perpendicular to barb 54. In someembodiments, the third barb 55 points inwards towards a central axis ofthe fastener and thus does not increase the overall width of thefastener profile.

Depending on the embodiment, the fastener 10 may have a width W1extending between the exterior sides of the two legs of about 4 mm to4.9 mm, 4.1 mm to 4.8 mm, 4.2 mm to 4.7 mm, 4.3 mm to 4.6 mm, or 4.4 mmto 4.5 mm inclusive. However, it should be understood that othersuitable widths are possible, as this aspect is not so limited.

As also shown in FIG. 3, the fastener may have a height H1 from a topsurface of the fastener to the distal pointed tips of the legs of about3 mm to 6.5 mm, 3.5 mm to 5 mm, or 4 mm to 4.5 mm, inclusive. However,it should be understood that other suitable heights are possible, asthis aspect is not so limited.

In addition to the general structure described above, the backspan 36can include a central pad 30. As best seen in FIG. 3, the central pad 30may protrude downward slightly from the bottom surface 25 of thebackspan. Without wishing to be bound by theory, such a protrusion 31may help the fastener to maintain flush contact with an underlyingprosthesis and/or tissue once it has been deployed. The central pad 30may have a height H2 of about 0.25 mm to 1 mm, 0.35 mm to 0.9 mm, 0.45mm to 0.8 mm, or 0.55 mm to 0.7 mm, inclusively. The central pad 30 mayalso extend between about 0 mm to 0.65 mm inclusively below the bottomsurface 25 of the backspan. In other embodiments, the central pad 30 mayextend inclusively between about 0.1 mm to 0.65 mm, 0.2 mm to 0.65 mm,0.3 mm to 0.65 mm, 0.4 mm to 0.65 mm, 0.5 mm to 0.65 mm, or any otherappropriate distance below the bottom surface 25. Additionally, thesurgical fastener may include a transition 27 from the bottom surface 25of the backspan to the bottom of the central pad 30 that may be curvedin a concave downwards shape as depicted in the figure. However, inother embodiments, the transition 27 may be concave upwards, a flatslant, rounded, chamfered, or any other suitable shape. While thecentral pad 30 has been depicted as protruding below the bottom surface25 of the backspan, it should be appreciated that in some embodiments,the bottom of the central pad may be flush with the bottom surface 25 ofthe backspan such that no transition between the two exists.

In some embodiments, the transition 29 from the top surface 26 of thebackspan 36 to the top surface of the central pad 30 is curved. As shownin FIG. 3, in some embodiments, the transition 29 is concave downwards.In other embodiments, the transition may be concave upwards, a flatslant, rounded, chamfered, or any other suitable shape. However, itshould be appreciated that in some embodiments, the top surface 26 iscoplanar with the top of the central pad 30 such that no transitionbetween the two exists.

In some embodiments, the central pad of the backspan may be thicker thaneach of the legs and/or a portion of the backspan attached to thecentral pad. For example, as shown in FIG. 2, the thickness T2 ofcentral pad 30 may be greater than the thickness T1 of leg 20 which isalso the thickness of the backspan portions attached to the central pad.In some cases, having a central pad 30 with an increased thickness T2may increase the surface area of the fastener backspan 36, which mayfurther reduce the pressure applied to underlying material when thefastener is deployed. In one embodiment, the legs 20 may have athickness T1 of about 0.25 mm to 3.5 mm, 0.75 mm to 3.0 mm, 1.25 mm to2.5 mm, or 1.75 mm to 2 mm, inclusive. The central pad 30 of thefastener may have a thickness T2 of about 0.25 mm to 3.5 mm, 0.75 mm to3.0 mm, 1.25 mm to 2.5 mm, or 1.75 mm to 2 mm, inclusive. In someembodiments, the width W2 of the central pad is less than the width W1of the backspan. In other embodiments, however, the width of the centralpad is equal to the width of the backspan. While any appropriate widthmight be used, in one embodiment, the central pad may have a width W2 ofabout 0.25 mm to 3.5 mm, 0.75 mm to 3.0 mm, 1.25 mm to 2.5 mm, or 1.75mm to 2 mm, inclusive.

In view of the above, the central pad may have an area between about 0.1mm² to 10 mm², 1 mm² to 10 mm², 2 mm² to 10 mm², 5 mm² to 10 mm², or anyother appropriate area. Additionally, the backspan, which includes thecentral pad, may have an area between about 0.25 mm² to 10 mm², 1 mm² to10 mm², 2 mm² to 10 mm², 5 mm² to 10 mm², or any other appropriate area.Without wishing to be bound by theory, a surgical fastener including abackspan with dimensions as noted above, or other appropriate dimension,may be designed to provide a pressure that is greater than or equal to27.5 kPa (4 psi) and less than or equal to 275 kPa (40 psi) for aparticular deployment force. In other embodiments, the pressure may bebetween about 27.5 kPa (4 psi) to 200 kPa (29 psi), 27.5 kPa (4 psi) to150 kPa (21.8 psi), 27.5 kPa (4 psi) to 100 kPa (14.5 psi), 27.5 kPa (4psi) to 50 kPa (7.3 psi), or any other appropriate pressure. Typicaldeployment forces can be greater than or equal to about 4.4 N (1 lbf)and less than or equal to about 44 N (10 lbf). In other embodiments thedeployment force may be inclusively between about 4.4 N (1 lbf) to 30 N(6.8 lbf), 4.4 N (1 lbf) to 20 N (4.5 lbf), 4.4 N (1 lbf) to 10 N (2.3lbf), or any other appropriate deployment force.

As depicted in FIG. 4, the central pad 30 can include rounded corners 37connecting the central pad connects to the rest of the backspan.However, the corners 37 may be any other suitable shape includingchamfered, angled, or right angles as the current disclosure is not solimited.

According to one aspect, the fastener backspan width and thickness areselected to fit within a certain surgical port size while being bothwide and thick enough (width being in the X-direction and thicknessbeing in the Z direction, see FIG. 2) to reduce the pressure and/orincrease the holding strength applied to underlying materials to desiredthresholds. As an example, a common port size used in laparoscopicsurgeries is a 5 mm port. Therefore, in some embodiments, the fastenerdimensions are selected to be used with such a port.

As seen in FIGS. 2 and 4, in some embodiments, the central pad 30 of thefastener can include a through-hole 40. In such an embodiment, a mandrelor guide rod of the fastener deployment device 1 passes through thethrough-hole 40 of each fastener to guide and stabilize the fasteners asthey are moved distally through the fastener deployment device andsubsequently deployed. Alternatively or in addition to the above, thethrough-hole 40 may allow tissue ingrowth, which may help to stabilizethe fastener at the target implantation site.

According to one aspect, the fasteners may be shaped to be stackableinside a fastener deployment device. Therefore, in some embodiments, afastener deployment device includes a plurality of surgical fastenersthat are arranged in any appropriate fashion within the shaft. When thedistal-most fastener is deployed, the rest of the fasteners aresequentially advanced in a deployment direction. In some embodiments,the top surface 24 of the backspan of a fastener includes recesses (notdepicted) that are shaped and arranged to receive the distal ends of thelegs of a proximally located adjacent fastener (not depicted). Receivingand retaining the legs of one fastener within the recesses of anadjacent fastener may help to decease lateral slippage between adjacentfasteners as they are advanced distally through the fastener deploymentdevice. As a result, such a stacking feature may help fasteners toremain aligned within a fastener deployment device as the fasteners areadvanced. While a particular arrangement is described above, anysuitable stacking feature may be used, as this aspect is not so limited.

It should be appreciated that the fasteners shown in FIGS. 2-4 areillustrative embodiments, and that other arrangements are possible.Specifically, the fastener may have more than two legs. In such anembodiment, the fastener may have three or more legs, or any othernumber of legs, that are evenly spaced from one another. For instance,if the fastener has three legs, the legs could be spaced 120° apart fromone another. Similarly, if the fastener has four legs, the legs could bespaced 90° apart from one another. Alternatively, the legs might bespaced at regular intervals according to length. However, in otherembodiments, the legs may be spaced at irregular intervals.

The above aspects and embodiments may be employed in any suitablecombination, as the present invention is not limited in this respect.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated that various alterations,modifications, and improvements will readily occur to those skilled inthe art. Such alterations, modifications, and improvements are intendedto be part of this disclosure, and are intended to be within the spiritand scope of the invention. Accordingly, the foregoing description anddrawings are by way of example only.

What is claimed is:
 1. A surgical fastener including: a first leg; asecond leg; and a backspan extending from the first leg to the secondleg, the backspan including a central pad with a thickness greater thana thickness of the backspan extending between the central pad and eitherthe first leg or second leg, wherein the surgical fastener is a non-deforming fastener such that the first and second legs are constructedto remain in an open position after deployment of the fastener, andwherein thickness is measured in a direction that is transverse to botha direction the backspan extends and a direction that the legs extendfrom the backspan; and wherein the backspan and central pad aremonolithically formed, and wherein the central pad protrudes downwardpast a bottom surface of the backspan.
 2. The surgical fastener of claim1, wherein an area of the central pad is less than or equal to about 10mm² and greater than or equal to about 0.1 mm².
 3. The surgical fastenerof claim 1, further comprising at least one anchoring feature to anchorthe fastener into tissue.
 4. The surgical fastener of claim 3, whereinthe at least one anchoring feature comprises a barb that points in adirection that is perpendicular to the direction of a longest dimensionof the backspan.
 5. The surgical fastener of claim 1, wherein thebackspan includes at least one through-hole.
 6. The surgical fastener ofclaim 5, wherein the at least one through-hole is constructed andarranged to receive a guide rod.
 7. The surgical fastener of claim 1,wherein a width of the backspan is between 4 mm to 4.9 mm, inclusive. 8.A surgical fastener comprising: a first leg; a second leg; and abackspan extending from the first leg to the second leg, wherein an areaof the backspan is selected to apply a pressure to underlying tissuethat is greater than or equal to 27.5 kPa and less than or equal to 275kPa when the surgical fastener is deployed from an associated deploymentdevice with a deployment force that is greater than or equal to 4.4 Nand less than or equal to 44 N; wherein the backspan includes a centralpad with a thickness greater than a thickness of a portion of thebackspan attached to the central pad, wherein the backspan and centralpad are monolithically formed, and wherein the central pad protrudesdownward past a bottom surface of the backspan.
 9. The surgical fastenerof claim 8, further comprising at least one anchoring feature to anchorthe fastener into tissue.
 10. The surgical fastener of claim 8, whereinthe surgical fastener is a non-deforming fastener such that the firstand second legs are constructed to remain in an open position afterdeployment of the fastener.
 11. The surgical fastener of claim 10,wherein an area of the central pad is less than or equal to 10 mm² andgreater than or equal to than 0.1 mm².
 12. The surgical fastener ofclaim 10, wherein the backspan includes at least one through-hole thatis constructed and arranged to receive a guide rod.
 13. A surgicalfastener including: a first leg; a second leg; and a backspan extendingfrom the first leg to the second leg, the backspan having an area lessthan or equal to 10 mm2 and greater than or equal to 0.25 mm2, whereinthe surgical fastener is a non-deforming fastener such that the firstand second legs are constructed to remain in an open position afterdeployment of the fastener; and wherein the backspan includes a centralpad with a thickness greater than a thickness of a portion of thebackspan attached to the central pad, wherein the backspan and centralpad are monolithically formed, and wherein the central pad protrudesdownward past a bottom surface of the backspan.
 14. The surgicalfastener of claim 13, further comprising at least one anchoring featureto anchor the fastener into tissue.
 15. The surgical fastener of claim14, wherein the at least one anchoring feature comprises a barb thatpoints in a direction that is perpendicular to the direction of alongest dimension of the backspan.
 16. The surgical fastener of claim13, wherein the backspan includes at least one through-hole.
 17. Thesurgical fastener of claim 16, wherein the at least one through-hole isconstructed and arranged to receive a guide rod.
 18. The surgicalfastener of claim 13, wherein a width of the backspan is between 4 mm to4.9 mm, inclusive.
 19. The surgical fastener of claim 13, furthercomprising a central pad with a thickness greater than a thickness of aportion of the backspan attached to the central pad.